The process involves drying the sludge in multiple steps. First, methane is generated. Then, the methane is reheated to cook out a high concentration of hydrogen gas.

The process is envisioned as a source of hydrogen for use in fuel cell vehicles. Many automakers, including Toyota and Honda, are planning new fuel cell vehicles in the coming years.

The cars are seen as a boon to fighting carbon emissions because they convert hydrogen into electricity, while emitting only water vapor. But getting the initial hydrogen can be expensive and complicated.